Variety of Fruits, Veggies Best vs. Colon Cancer

Eating a Variety of Fruits and Vegetables

Fritschi and her co-authors based their findings on a comparison of 834 people who had been diagnosed with colon cancer and a comparison group of 939 people without cancer.

Participants completed a questionnaire about their food and alcohol intake a decade earlier since it takes years for colon cancer to develop, and information about current intake wouldn’t be as relevant. They also answered questions about their health history, such as their height and weight at age 20, their smoking status, and whether they had diabetes. Smoking, diabetes, and obesity are factors linked to risk for colon cancer.

“I think the message is a good one, and that is to eat a variety of fruits and vegetables,” Marji McCullough, ScD, RD, strategic director of nutritional epidemiology at the American Cancer Society, tells WebMD.

Meat Intake Might Have Played a Role

However, noted McCullough, who was not involved in the study, the authors did not account for the amount of red and processed meats in the study participants’ diets.

The World Cancer Research Fund International says there’s "strong evidence" that such meats increase risk of colon cancer, and people who eat lots of them usually eat fewer fruits and vegetables, McCullough says. The American Cancer Society also states that diets high in processed meats and red meat can increase the risk of colon cancer. So, she says, meat consumption, not fruit and vegetable intake, might explain the Australian researchers’ findings.

Fritschi says she and her co-authors looked in detail at meat consumption in only a subset of study participants, not enough to take into account in their analysis.

McCullough also says this type of research -- relying heavily on recall of diet in past years -- tends to find a stronger relationship between fruit and vegetable intake and colon cancer risk than studies that collect dietary information from people before they’re diagnosed.

The authors note that limitation in their study. “The problem of bias and memory is a real issue with dietary measurement,” Fritschi says. “We tried to do what we could, but it is a real problem for all these retrospective studies.”

The study appears in the October issue of the Journal of the American Dietetic Association.